The field of the disclosure relates generally to data reading devices, and particularly, to improved data reading devices for reading data from a reflective surface of electronic devices.
Optical codes, such as barcodes and other machine-readable indicia, appear in a variety of applications. There are a variety of forms, such as: linear barcodes (e.g., UPC code), 2D codes including stacked barcodes (e.g., PDF-417 code), and matrix codes (e.g., Datamatrix code, QR code, or Maxicode). There are several types of data readers used for reading these optical codes. The most common types of optical code readers are laser scanners and imaging readers. A laser scanner typically moves, i.e. scans, a laser light beam across the barcode. Imaging readers are typically used to capture a 2D image of an area, including the optical code or other scene, focused onto a detector array such as charge-coupled devices (CCDs) and complementary metal oxide semiconductor (CMOS) imagers. With some such imaging readers, it may be advantageous to provide a source of illumination that illuminates the optical code or other scene being imaged, to provide the required signal response in the imaging device. Such a source of illumination can reduce exposure time, thereby improving imager performance, especially in low ambient light conditions and when imaging moving items.
Typically, in a grocery or retail establishment, optical codes are often printed directly on items or printed on a sticker that is thereafter affixed to the item. These optical codes are usually printed or located on surfaces with little or no reflectivity so that illumination from a data reading device is not reflected back toward the data reading device, which may render the image obtained by the data reader difficult to process.
Businesses have begun sending optical codes to customers who display such optical codes on a portable electronic device, such as a mobile telephone or cell phone, personal digital assistant, palm, tablet, or laptop computer, or other suitable device having an electronic display, such as a liquid crystal display (LCD). For example, an airline passenger may display an optical code on a portable electronic device for an airline employee to read using a data reader as verification of the passenger's ticket. Or, a customer in a store may display an optical code on a portable electronic device for a cashier to read using a data reader to redeem a coupon. Optical codes are also included on other items having highly, or relatively highly, reflective surfaces, for example, but not limited to, identification (ID) cards, aluminum cans, and objects in plastic packaging.
The present inventors have recognized that optical codes presented on, or under, a highly, or relatively highly, reflective surface are typically difficult to decode using general-purpose data readers. For example, the present inventors have recognized that general-purpose data readers commonly use artificial illumination to illuminate an object bearing an optical code to create an image of the optical code having sufficient contrast for decoding the optical code. The present inventors have also recognized that highly, or relatively highly, reflective surfaces bearing optical codes commonly reflect a large amount of such artificial illumination resulting in a saturated, or partially saturated, image that does not have sufficient contrast for decoding the optical code because all, or portions, of the image appear light, or white. However, simply eliminating the artificial illumination is not a practicable solution since the data reader may not otherwise have sufficient illumination to read optical labels from non-reflective items, which would likely be the most common use of the data reader.
Other general-purpose data readers may be capable of detecting the presence of an electronic device or other reflective surface by detecting the amount of light reflected toward the data reader. In some systems, the data reader may attempt to switch from a primary data reading mode (e.g., reading data from items having non-reflective surfaces or surfaces with relatively low reflectivity) to a secondary reading mode (e.g., reading data from items having highly reflective surfaces) in response to detecting the electronic device. However, many existing data readers have difficulty reliably detecting the presence of an electronic device. In such cases, the data reader may improperly switch to the secondary reading mode, thereby being unable to read normal optical codes on non-reflective surfaces, or may fail to properly switch over when presented with an electronic device, thereby being unable to read data from highly-reflective surfaces of the electronic device.
Still other data readers attempt to divide the imager between the primary and secondary reading modes, dedicating a specific percentage of the imager exclusively to each reading mode. Accordingly, the imager includes an area specifically dedicated to detecting an electronic device and reading data therefrom, and an area specifically dedicated to reading data from non-reflective surfaces. However, the present inventors have recognized that a disadvantage of this configuration is that the data reader dedicates significant resources for reading data from electronic devices regardless of whether such a device is present or not, which detrimentally affects overall performance of the data reader by reducing resources that may be used for reading data from non-reflective surfaces, which as noted previously, is likely the most common use of the data reader.
Thus, the present inventors have identified a need for a general-purpose data reader that has improved versatility in handling reading of optical codes appearing on (or behind) highly, or relatively highly, reflective surfaces, as well as reading optical codes appearing on surfaces have no or little reflectivity.